The invention is related to a coating composed of an optically effective layer system, for substrates, whereby the layer system has a high antireflective effect.
There is a wide range of layer systems for substrates, particularly for glass, which fulfill certain optical functions. The present invention involves a type of layer system using antireflective layers, or respectively, antireflective layer systems.
The German publication DE-OS 3,629,996 revealed an adaptor unit/aggregate for the cathode ray tube of monitors, television sets and such, composed of a glass disk, particularly a gray glass disk, a frontside antireflection device and a backside absorption coating, whereby the absorption coating comprises metal atoms.
In this German publication it is suggested that the absorption coating is structured in one-layered fashion from chrome, a chrome/nickel alloy or silicides, established and grounded antistatically, and provided with a thickness which lowers the light transmission compared to the uncoated glass disk by approximately one third.
The U.S. Pat. No. 3,854,796 suggests another coating for the reduction of reflection. The coating is to be applied on a substrate having a plurality of layers. In the sequence beginning at the substrate, the '796 patent describes the following arrangement: three groups of at least two lambda/4-layers, the successive layers of the first group have a refractive index lying below the refractive index of the substrate. The layers of the second group have an increasing refractive index and the layers of the third group have a refractive index below that of the substrate. More details can be ascertained from the cited '796 patent.
In U.S. Pat. No. 3,761,160 a broadband-antireflection-coating coated onto substrates is suggested. At least four layers are disclosed for glass with a high index and at least six layers are disclosed for glass with a low index. More details can be learned from the cited '160 patent.
U.S. Pat. No. 3,695,910 describes a method for the application of a antireflective coating on a substrate. This coating is composed of several individual layers. The method for the application of the antireflection coatings ensues under vacuum, namely with the use of electron beams.
U.S. Pat. No. 3,829,197 describes a antireflection coating fashioned as a multilayer system. This coating is to be applied on a strongly refractive substrate. The layer system is composed of five individual layers which are mutually adapted with regard to their refractive indices and optical thicknesses. This adaptation is to achieve a favorable antireflection curve with a broad, flat, center part.
Swiss patent 223,344 deals with a coating for the reduction of surface reflection. The coating is composed of at least three layers with various refraction coefficients. The reduction of the surface reflection can be achieved, according to this reference, by a certain selection of refraction coefficients of the individual layers.